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"This U.S. Bureau of Mines report describes the development of a yielding steel post for underground mine support. The report covers concept development, laboratory tests, modifications, and field evaluations. The objective of this work was to develop a stiff support member capable of both supporting high loads and yielding when excessive amounts of mine entry closure were present. The 6- to 7-ft steel post was designed to yield nearly 2 ft while maintaining a 45-ton (force) load. The post is a three-piece unit consisting of top and bottom telescoping legs and a separate foot bracket. It develops its load-carrying characteristics when the lower pipe, with an attached interference ring, is forced into the larger top pipe. Laboratory tests were used to determine critical loads and post performance for various post lengths. Field tests showed that the posts could perform in actual mining conditions. The post has the ability to provide support in highly yielding ground and also, because of its slender profile, enhance ventilation and provide more area for travelways and escapeways. The design is simple enough to allow for fabrication at most mine shop facilities." - NIOSHTIC-2

A new generation of hydraulic mine support prestressing devices has been developed. These thin-walled steel shells are machine-welded and can be inflated with water or any liquid to provide prestressing for a wide variety of roof support products ran...

Roof support systems are necessary to provide stable mine openings and much research has been conducted to design a variety of roof support systems that will function in various manners to ensure that stable ground conditions are achieved. Despite th...

"The Bureau of Mines examined previous research on rib stability in an effort to develop a practical approach to understanding, characterizing, and controlling weak rib conditions in underground coal mines. Because success in stabilizing ribs depends...

Many of the support concepts currently used in the United States originated in South Africa. These products include the Hercules Crib, Propsetter, MX Prop, Rocprop, and Spider Prop. Another recent development has been the introduction of hydraulic pr...

Mines in the western United States have had limited choices for standing support. Wood cribs were often too soft and unstable. The introduction of the Can support in the earl v 1990s provided an effective alternative, (lilt/ it remains the dominant f...